Statspack is a set of performance monitoring and reporting utilities provided by Oracle from Oracle8i and above. Statspack provides improved BSTAT/ESTAT functionality, though the old BSTAT/ESTAT scripts are still available. For more information about STATSPACK, read the documentation in file $ORACLE_HOME/rdbms/admin/spdoc.txt.
Install Statspack:
cd $ORACLE_HOME/rdbms/admin
sqlplus “/ as sysdba” @spdrop.sql — Install Statspack –
sqlplus “/ as sysdba” @spcreate.sql– Enter tablespace names when prompted
Use Statspack:
sqlplus perfstat/perfstat
exec statspack.snap; — Take a performance snapshots
exec statspack.snap;
o Get a list of snapshots
select SNAP_ID, SNAP_TIME from STATS$SNAPSHOT;
@spreport.sql — Enter two snapshot id’s for difference report
Other Statspack Scripts:
.sppurge.sql – Purge a range of Snapshot Id’s between the specified begin and end Snap Id’s
.spauto.sql – Schedule a dbms_job to automate the collection of STATPACK statistics
.spcreate.sql – Installs the STATSPACK user, tables and package on a database (Run as SYS).
.spdrop.sql – Deinstall STATSPACK from database (Run as SYS)
.sppurge.sql – Delete a range of Snapshot Id’s from the database
.spreport.sql – Report on differences between values recorded in two snapshots
.sptrunc.sql – Truncates all data in Statspack tables

Q.What are the common RMAN errors (with solutions)? (for DBA)
Some of the common RMAN errors are:
RMAN-20242: Specification does not match any archivelog in the recovery catalog.
Add to RMAN script: sql ‘alter system archive log current';
RMAN-06089: archived log xyz not found or out of sync with catalog
Execute from RMAN: change archivelog all validate;

Q.What ERASE package procedure does ?

Erase removes an indicated global variable.

Q.What is the use of break group? What are the various sub events a mouse double click event involves?

A break group is used to display one record for one group ones. While multiple related records in other group can be displayed.

Q.When the form is running in DEBUG mode, If you want to examine the values of global variables and other form variables, What package procedure command you would use in your trigger text ?

Break.
SYSTEM VARIABLES

Q.The value recorded in system.last_record variable is of type
a.Number
b.Boolean
c.Character.
b.Boolean.

Q.What is the difference between NAME_IN and COPY ?
Copy is package procedure and writes values into a field.
Name in is a package function and returns the contents of the variable to which you apply.

Q.How do u implement the If statement in the Select Statement
We can implement the if statement in the select statement by using the Decode statement. e.g. select DECODE (EMP_CAT,’1′,’First’,’2′,’Second’Null); Here the Null is the else statement where null is done .

Q.What are the inline and the precompiler directives
The inline and precompiler directives detect the values directly

Q.How do you use the same lov for 2 columns
We can use the same lov for 2 columns by passing the return values in global values and using the global values in the code

Q.How many minimum groups are required for a matrix report
The minimum number of groups in matrix report are 4

Q.What are the different objects that you cannot copy or reference in object groups?

Objects of different modules
Another object groups
Individual block dependent items
Program units.

Q.What is the difference between static and dynamic lov
The static lov contains the predetermined values while the dynamic lov contains values that come at run time

Q.How does one manage Oracle database users? (for DBA)
Oracle user accounts can be locked, unlocked, forced to choose new passwords, etc. For example, all accounts except SYS and SYSTEM will be locked after creating an Oracle9iDB database using the DB Configuration Assistant (dbca). DBA’s must unlock these accounts to make them available to users.
Look at these examples:
ALTER USER scott ACCOUNT LOCK — lock a user account
ALTER USER scott ACCOUNT UNLOCK; — unlocks a locked users account
ALTER USER scott PASSWORD EXPIRE; — Force user to choose a new password

Q.How many types of Exceptions are there
There are 2 types of exceptions. They are
a) System Exceptions
e.g. When no_data_found, When too_many_rows
b) User Defined Exceptions
e.g. My_exception exception
When My_exception then

Q.What is the difference between DBFile Sequential and Scattered Reads?(for DBA)
Both “db file sequential read” and “db file scattered read” events signify time waited for I/O read requests to complete. Time is reported in 100’s of a second for Oracle 8i releases and below, and 1000’s of a second for Oracle 9i and above. Most people confuse these events with each other as they think of how data is read from disk. Instead they should think of how data is read into the SGA buffer cache.
db file sequential read:
A sequential read operation reads data into contiguous memory (usually a single-block read with p3=1, but can be multiple blocks). Single block I/Os are usually the result of using indexes. This event is also used for rebuilding the control file and reading data file headers (P2=1). In general, this event is indicative of disk contention on index reads.
db file scattered read:
Similar to db file sequential reads, except that the session is reading multiple data blocks and scatters them into different discontinuous buffers in the SGA. This statistic is NORMALLY indicating disk contention on full table scans. Rarely, data from full table scans could be fitted into a contiguous buffer area, these waits would then show up as sequential reads instead of scattered reads.
The following query shows average wait time for sequential versus scattered reads:
prompt “AVERAGE WAIT TIME FOR READ REQUESTS”
select a.average_wait “SEQ READ”, b.average_wait “SCAT READ”
from sys.v_$system_event a, sys.v_$system_event b
where a.event = ‘db file sequential read’
and b.event = ‘db file scattered read';

Sure there are, but it is hard to find them. Look at these examples:
From Server Manager (Oracle7.3 and above): ORADEBUG HELP
It looks like one can change memory locations with the ORADEBUG POKE command. Anyone brave enough to test this one for us? Previously this functionality was available with ORADBX (ls -l $ORACLE_HOME/rdbms/lib/oradbx.o; make -f oracle.mk oradbx) SQL*Plus: ALTER SESSION SET CURRENT_SCHEMA = SYS

Q.What is an OLE?

Object Linking & Embedding provides you with the capability to integrate objects from many Ms-Windows applications into a single compound document creating integrated applications enables you to use the features form .

Q.If the maximum record retrieved property of the query is set to 10 then a summary value will be calculated?